The internal combustion engine has long been lubricated by oil. The oil is pooled in a pan-like structure called an oil pan, which is attached to the bottom of the engine. When the oil breaks down (i.e., loses its lubricating efficiency during use), it must be periodically removed from the oil pan and fresh oil must be added to the oil pan in a process known as an oil change. Many oil changes occur over the lifetime of the engine, and in order to accommodate numerous oil changes, the oil pan is fabricated with a drain hole through which the broken down oil is normally removed. However, in order for the oil to pool in the oil pan, the drain hole must be sealed. Likewise, in order for the oil to be drained from the oil pan, the drain hole must be unsealed. To accomplish this, the perimeter of the drain hole is usually fabricated with a ring shaped insert positioned therein. The insert has threads which permit a bolt-like threaded drain plug to be screwed into the threads of the insert, to seal the drain hole, and unscrewed from the threads, to unseal the drain hole.
The repetitious screwing and unscrewing of the threaded-drain plug into and out of the threaded-drain hole results in the threads of the insert and the threads of the drain plug becoming worn over long periods of use. Also, metal particles that are not cleared out the threads of the insert and the threads of the drain plug following each oil change cause wear on the threads. When the wear on the threads of the insert and the threads of the drain plug reaches a point where the drain plug is no longer able to be screwed into in the drain hole without it leaking, or it becomes completely unscrewed from the drain hole (i.e., by the vibrations of the oil pan during the operation of the engine), an accidental oil spill will occur.
An accidental oil spill that occurs in this manner creates an adverse impact on the environment, a safety hazard for slipping or falling, and damage to the engine (i.e., through extended operation of the engine without oil in the oil pan). Also, the threads of the insert and the threads of the drain plug are occasionally damaged by improper drain plug installation procedures such as when the drain plug is over tightened or when its threads are cross-threaded with the threads of the drain hole.
Presently, the repair of a worn or cross-threaded drain plug may be accomplished by replacing the worn drain plug with a new one. The repair of the worn or cross-threaded threads of the threaded-insert of the drain hole is usually accomplished by replacing the entire oil pan, which is costly and time consuming. What is needed, but has yet to be provided, is an oil drain plug which completely replaces the wear and failure prone threads of conventional threaded drain plugs.